Stacked Processor-Memory Rings for Parallel ML Communication

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Solution Overview

Problem

Current stacked device systems face limitations in efficiently interconnecting multiple processing units and memory devices for parallel machine learning tasks, particularly in implementing distributed and parallel algorithms like Ring-AllReduce, due to constraints in data and control signal communication through shared through-silicon via connections.

Innovation Solution

The system employs a ring topology interconnection configuration using through-silicon via connections between DRAM and processor dies, enabling efficient communication and parallel processing by configuring separate ring topologies for different machine learning tasks, allowing concurrent training of neural network models across device stacks using a handshake protocol.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If shared through-silicon via connections are used for interconnecting device stacks, then vertical integration and compact form factor are achieved, but communication efficiency and scalability for parallel processing are limited

Engineering Contradiction:
Improveform factorVSAvoidparallel processing efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The system segments the monolithic interconnection into multiple independent ring topologies, where each ring can operate autonomously for different machine learning tasks. This allows parallel processing across device stacks without contention on shared via connections, resolving the contradiction between compact vertical integration and parallel processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from purely vertical through-silicon via connections to a hybrid architecture that incorporates horizontal ring topology interconnections. This dimensional change enables data to flow laterally across device stacks, bypassing the bottleneck of shared vertical vias and enabling scalable parallel processing while maintaining the compact stacked form factor.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multiple device stacks are interconnected for distributed machine learning, then processing capability is improved, but system complexity and interconnection management become problematic

Engineering Contradiction:
Improveprocessing capabilityVSAvoidinterconnection management
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The ring topology interconnection is designed as a universal communication fabric that can handle multiple machine learning workloads simultaneously. Each device stack can participate in multiple rings and perform different functions (training, inference, data movement) through the same physical infrastructure, reducing interconnection management complexity while scaling processing capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically configures ring topologies and assigns device stacks to different rings based on workload requirements. This dynamic reconfiguration capability allows the system to adapt to varying processing demands without requiring complex static interconnection designs, thereby improving processing capability while managing complexity through software-controlled flexibility.

Inventive Principle:
Principle #15Dynamics

3Productivity

If concurrent training of multiple neural network models is implemented, then system utilization is improved, but communication protocol complexity increases

Engineering Contradiction:
Improvesystem utilizationVSAvoidcommunication protocol
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces a protocol abstraction layer that mediates communication between device stacks performing concurrent neural network training. This intermediary protocol manages data flow, synchronization, and coordination across multiple concurrent training tasks, enabling high system utilization while shielding the underlying complexity of simultaneous multi-model training communications.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS12124392B2Stacked device system
Publication Date: 2024.10.22 RAMBUS INC
  • US12124392B2 patent drawing
  • US12124392B2 patent drawing
  • US12124392B2 patent drawing

AI summary

Multiple device stacks are interconnected in a ring topology. The inter-device stack communication may utilize a handshake protocol. This ring topology may include the host so that the host may initialize and load the device stacks with data and/or commands (e.g., software, algorithms, etc.). The inter-device stack interconnections may also be configured to include/remove the host and/or to implement varying numbers of separate ring topologies. By configuring the system with more than one ring topology, and assigning different problems to different rings, multiple, possibly unrelated, machine learning tasks may be performed in parallel by the device stack system.